The invention relates to rotary power devices, and more particularly to internal combustion engines, pumps, compressors, fluid-driven motors, fluid-driven compressors and pumps and throttling devices in which the rotor includes at least two pivoting pistons.
This invention relates to a rotary power device comprising pivotable swingable pistons. Such devices are characterized in having pistons or vanes that execute angular reciprocating movement within chambers in a rotating member and that engage a cam track. An example of rotary devices of the above type can be found in U.S. Pat. No. 4,038,948 to Blackwood. Some of these types of devices can function as internal combustion engines in which gas is initially entrapped within a rotor chamber as a piston swings outward towards a cam surface receding from the rotor and is then compressed when the piston swings inward as the cam surface approaches the rotor. The compressed gases ignite at minimum volume and the ignited gases exert a force on the outwardly swinging piston which, in turn, exerts a force through roller cam followers on the relatively inclined cam track, the reaction to which provides the necessary torque to rotate the rotor. Although such power devices have been proven to be theoretically functional, they are characterized in some respects with complexities associated with cam arrangement, piston shape, and inlet and outlet arrangements, all of which make them costly to manufacture, assemble, and maintain.
A preferred pivoting piston rotary power device of the invention comprises a stator and a rotor. The preferred stator includes a tubular external stator portion defining an internal volume having at least one pair of cam tracks spaced apart along an axis of rotation. These cam tracks have diametrically opposed eccentricities with respect to the axis. The internal volume is defined by a tubular middle portion, a front end portion and a back end portion of the external portion of the stator. The front end portion has a central throughhole for receiving a shaft and the tubular middle portion has at least two elliptical cam tracks disposed on its inner surface. There is also an internal cylindrical stator portion projecting from the back end wall portion into the internal volume along an axis of the device. The preferred internal stator portion has a plurality of passageways formed in it, each of which comprises a channel parallel to the axis communicating with at least one respective radial port formed in a periphery of the internal stator. The rotor comprises a shaft extending along the axis of the device and journaled within the central throughhole in the front end portion of the stator. The rotor also comprises a cylindrical block having a central cylindrical bore for receiving the internal stator. The block is rotatable within that portion of the internal volume lying between the internal stator portion and the external stator portion. The block further comprises at least two working compartments spaced apart along the axis of the device so that each is associated with a respective one of the cam tracks. In preferred embodiments, the block comprises at least two sets, arranged as circular arrays, of a selected number of working compartments equi-angularly spaced apart about the axis of the device. Each of these working compartments preferably defines a respective sector of a respective hollow cylinder having a respective cylinder axis disposed parallel to the axis of the device and proximal to the periphery of the rotor. Moreover, each compartment is open to an outer peripheral surface of the block and has a radial, inwardly directed, opening communicating with the central cylindrical bore. In addition, the preferred device comprises twice the selected number of pivoting piston assemblies, each of which comprises a respective sector-shaped portion of a solid cylinder received in a respective working compartment, and having a respective pivot axis coinciding with the respective cylinder axis of the working compartment in which it is received. Each piston assembly also comprises a roller cam follower for engaging the respective cam track on the inner wall of the middle portion of the external stator.
Alternate embodiments of the invention can be made by adding additional pairs of cam tracks to the external stator and additional pairs of arrays of working compartments and piston assemblies to the rotor. Thus, more generally, a device of the invention comprises an external stator portion comprising a chosen even number, equal to or greater than two, of eccentric cam tracks disposed on an inner surface thereof, and a rotor comprising the chosen even number of working compartments axially spaced apart so that each of the working compartments is associated with a respective one of the cam tracks. The device moreover comprises a plurality of pivoting piston assemblies, each piston assembly received in a respective working compartment and comprising a roller cam follower for engaging the cam track associated with the compartment in which it is received.
A general object of the present invention is to provide an improved two-phase swinging piston rotary power device that can overcome the problems presently encountered in this class of rotary engines.
Another general object of the invention is to provide a rotary power device light in weight, small in size and having a minimum number of parts.
A more specific object of the invention is to provide a family of rotary power devices that can be easily converted from one type to another, such as a pump, compressor, hydraulic motor, fluid driven pump or compressor, or a compound internal combustion engine and compressor by a simple modification or replacement of a central stationary member.
These and other objects and advantages of the present invention will be apparent from the following detailed description and the appended claims.